A non-contact IC card does not include a power supply therein, and makes a built-in circuit operate by receiving an electric power supplied by an external radio wave. Generally, an AC magnetic field of 13.56 MHz is externally supplied to such a non-contact IC card, and rectified to a DC power supply by a full-wave rectifier circuit built in the non-contact IC card, to be used as an internal power supply. The full-wave rectifier circuit normally includes a bridge circuit formed of four diodes, and with respect to a magnetic field supplied to an antenna formed of an inductance element such as a coil, the inductance element generates an induced current, and the induced current is supplied to the bridge circuit. The induced current is an AC current whose polarity is inverted in accordance with a polarity inversion of the magnetic field, and thus is rectified to a DC current by a rectifier circuit formed of the bridge circuit.
The diode forming the full-wave rectifier circuit is structured through PN junction in a P-well formed in a P-type substrate. The P-well is formed in an N-well for the purpose of being electrically separated from the P-type substrate. Specifically, there is provided a triple-well structure in which the P-well in which the diode is formed is formed in the N-well formed in the P-type substrate. Regarding the diode with triple-well structure, there has been proposed a technology aiming to suppress a generation of a substrate current.
However, in a full-wave rectifier circuit including a bridge circuit formed of conventional diodes, including diodes aiming to suppress the generation of the substrate current, as a frequency of an input signal increases, a rectification characteristic is likely to be reduced.
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